Britain's spy agency GCHQ has surreptitiously tapped into vast
volumes of data drawn from the fiber-optic cables that carry the world's
phone calls and Internet traffic, and is sharing with its U.S.
counterpart - the National Security Agency (NSA) - personal information
it finds, according to a new finding among top-secret documents leaked by former government contractor Edward Snowden.

The
Guardian newspaper, which first reported on NSA programs designed to
track suspected terrorists by secretly culling U.S. phone records and
mining user data from major Internet servers, published a story Friday on the operation, code-named "Tempora." The 18-month-old program
allows GCHQ to not only access from anyone in the world communications
ranging from recordings of phone calls to Facebook entries and browser
histories, but also store it for 30 days in order to sort and analyze
it.

Documents
leaked by Snowden show GCHQ was dealing with 600 million "telephone
events" per day. The Guardian said it "understands that a total of
850,000 NSA employees and U.S. private contractors with top-secret
clearance had access" to the databases.